经常会用到JSON格式才处理，尤其是在Http请求的时候，网上可以找到很多json处理的相关工具，如org.json和json-lib，下面两段源代码是分别使用这两个工具解析和构造JSON的演示程序。  //这是使用json-lib的程序：  import JAVA.util.HashMap;  import JAVA.util.Map;    import net.sf.json.JSONObject;    public class Test {        public static void main(String[] args) {          String json = "{\"name\":\"reiz\"}";          JSONObject jsonObj = JSONObject.fromObject(json);          String name = jsonObj.getString("name");                  jsonObj.put("inITial", name.substring(0, 1).toUpperCASE());            String[] likes = new String[] { "JAVAScript", "Skiing", "Apple Pie" };          jsonObj.put("likes", likes);            Map <String, String> ingredients = new HashMap <String, String>();          ingredients.put("apples", "3kg");          ingredients.put("sugar", "1kg");          ingredients.put("pastry", "2.4kg");          ingredients.put("bestEaten", "outdoors");          jsonObj.put("ingredients",ingredients);                  System.out.println(jsonObj);      }  }  //这是使用org.json的程序：  import JAVA.util.HashMap;  import JAVA.util.Map;    import org.json.JSONException;  import org.json.JSONObject;    public class Test {        public static void main(String[] args) throws JSONException {          String json = "{\"name\":\"reiz\"}";          JSONObject jsonObj = new JSONObject(json);          String name = jsonObj.getString("name");            jsonObj.put("inITial", name.substring(0, 1).toUpperCASE());            String[] likes = new String[] { "JAVAScript", "Skiing", "Apple Pie" };          jsonObj.put("likes", likes);            Map <String, String> ingredients = new HashMap <String, String>();          ingredients.put("apples", "3kg");          ingredients.put("sugar", "1kg");          ingredients.put("pastry", "2.4kg");          ingredients.put("bestEaten", "outdoors");          jsonObj.put("ingredients", ingredients);          System.out.println(jsonObj);            System.out.println(jsonObj);      }  }  //两者在生成json的时候几乎是相同的，但org.json比json-lib要轻量得多，前者没有任何依赖，而后者要依赖ezmorph和commons的lang、logging、beanutils、collections等组件。但是往往使用的时候，我们会操作Bean和Json的转换，org.json可以从Bean转到json，似乎不能从json转到Bean。下面是我找的几个例子。

public class JsonUtil {                                 public static Object getObject4JsonString(String jsonString, Class pojoCalss) {                 Object pojo;                 JSONObject jsonObject = JSONObject.fromObject(jsonString);                 pojo = JSONObject.toBean(jsonObject, pojoCalss);                 return pojo;             }                                         public static Map getMap4Json(String jsonString) {                 JSONObject jsonObject = JSONObject.fromObject(jsonString);                 Iterator keyIter = jsonObject.keys();                 String key;                 Object value;                 Map valueMap = new HashMap();                         while (keyIter.hasNext()) {                     key = (String) keyIter.next();                     value = jsonObject.get(key);                     valueMap.put(key, value);                 }                         return valueMap;             }                                         public static Object[] getObjectArray4Json(String jsonString) {                 JSONArray jsonArray = JSONArray.fromObject(jsonString);                 return jsonArray.toArray();                     }                                         public static List getList4Json(String jsonString, Class pojoClass) {                         JSONArray jsonArray = JSONArray.fromObject(jsonString);                 JSONObject jsonObject;                 Object pojoValue;                         List list = new ArrayList();                 for (int i = 0; i < jsonArray.size(); i++) {                             jsonObject = jsonArray.getJSONObject(i);                     pojoValue = JSONObject.toBean(jsonObject, pojoClass);                     list.add(pojoValue);                         }                 return list;                     }                                         public static String[] getStringArray4Json(String jsonString) {                         JSONArray jsonArray = JSONArray.fromObject(jsonString);                 String[] stringArray = new String[jsonArray.size()];                 for (int i = 0; i < jsonArray.size(); i++) {                     stringArray[i] = jsonArray.getString(i);                         }                         return stringArray;             }                                         public static Long[] getLongArray4Json(String jsonString) {                         JSONArray jsonArray = JSONArray.fromObject(jsonString);                 Long[] longArray = new Long[jsonArray.size()];                 for (int i = 0; i < jsonArray.size(); i++) {                     longArray[i] = jsonArray.getLong(i);                         }                 return longArray;             }                                         public static Integer[] getIntegerArray4Json(String jsonString) {                         JSONArray jsonArray = JSONArray.fromObject(jsonString);                 Integer[] integerArray = new Integer[jsonArray.size()];                 for (int i = 0; i < jsonArray.size(); i++) {                     integerArray[i] = jsonArray.getInt(i);                         }                 return integerArray;             }                                 public static Date[] getDateArray4Json(String jsonString, String DataFormat)                     throws ParseException {                         JSONArray jsonArray = JSONArray.fromObject(jsonString);                 Date[] dateArray = new Date[jsonArray.size()];                 String dateString;                 Date date;                         for (int i = 0; i < jsonArray.size(); i++) {                     dateString = jsonArray.getString(i);                     date = DateUtil.parseDate(dateString, DataFormat);                     dateArray[i] = date;                         }                 return dateArray;             }                                         public static Double[] getDoubleArray4Json(String jsonString) {                         JSONArray jsonArray = JSONArray.fromObject(jsonString);                 Double[] doubleArray = new Double[jsonArray.size()];                 for (int i = 0; i < jsonArray.size(); i++) {                     doubleArray[i] = jsonArray.getDouble(i);                         }                 return doubleArray;             }                                         public static String getJsonString4JavaPOJO(Object javaObj) {                         JSONObject json;                 json = JSONObject.fromObject(javaObj);                 return json.toString();                     }                                 public static String getJsonString4JavaPOJO(Object javaObj,                     String dataFormat) {                         JSONObject json;                 JsonConfig jsonConfig = configJson(dataFormat);                 json = JSONObject.fromObject(javaObj, jsonConfig);                 return json.toString();                     }                                 public static JsonConfig configJson(String datePattern) {                 JsonConfig jsonConfig = new JsonConfig();                 jsonConfig.setExcludes(new String[] { "" });                 jsonConfig.setIgnoreDefaultExcludes(false);                 jsonConfig.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);                 jsonConfig.registerJsonValueProcessor(Date.class,                         new JsonDateValueProcessor(datePattern));                         return jsonConfig;             }                                         public static JsonConfig configJson(String[] excludes, String datePattern) {                 JsonConfig jsonConfig = new JsonConfig();                 jsonConfig.setExcludes(excludes);                 jsonConfig.setIgnoreDefaultExcludes(true);                 jsonConfig.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);                 jsonConfig.registerJsonValueProcessor(Date.class,                         new JsonDateValueProcessor(datePattern));                         return jsonConfig;             }                 }          package com.baiyyy.polabs.util.json;                 import java.text.SimpleDateFormat;         import java.util.Date;                 import net.sf.json.JsonConfig;         import net.sf.json.processors.JsonValueProcessor;                         public class JsonDateValueProcessor implements JsonValueProcessor {                               private String format = "yyyy-MM-dd HH:mm:ss";                           public JsonDateValueProcessor() {                           }                           public JsonDateValueProcessor(String format) {                    this.format = format;                }                           public Object processArrayValue(Object value, JsonConfig jsonConfig) {                    String[] obj = {};                    if (value instanceof Date[]) {                        SimpleDateFormat sf = new SimpleDateFormat(format);                        Date[] dates = (Date[]) value;                        obj = new String[dates.length];                        for (int i = 0; i < dates.length; i++) {                            obj[i] = sf.format(dates[i]);                        }                    }                    return obj;                }                           public Object processObjectValue(String key, Object value, JsonConfig jsonConfig) {                    if (value instanceof Date) {                        String str = new SimpleDateFormat(format).format((Date) value);                        return str;                    }                    return value =http://www.mamicode.com/= null ? null : value.toString();                }                           public String getFormat() {                    return format;                }                           public void setFormat(String format) {                    this.format = format;                }                       }    

Json与javaBean之间的转换工具类http://www.oschina.net/code/piece_full?code=17607
 import java.lang.reflect.Field;  import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Set;  import net.sf.json.JSONArray; import net.sf.json.JSONObject; import net.sf.json.JsonConfig;  /**  * Json与javaBean之间的转换工具类  *   * @author 晚风工作室 www.soservers.com  * @version 20111221  *   * {@code   现使用json-lib组件实现  *          需要  *              json-lib-2.4-jdk15.jar  *              ezmorph-1.0.6.jar  *              commons-collections-3.1.jar  *              commons-lang-2.0.jar  *          支持  * }  */ public class JsonPluginsUtil {         /**        * 从一个JSON 对象字符格式中得到一个java对象        *         * @param jsonString        * @param beanCalss        * @return        */    @SuppressWarnings("unchecked")     public static <T> T jsonToBean(String jsonString, Class<T> beanCalss) {                   JSONObject jsonObject = JSONObject.fromObject(jsonString);         T bean = (T) JSONObject.toBean(jsonObject, beanCalss);                   return bean;               }       /**        * 将java对象转换成json字符串        *      * @param bean        * @return        */    public static String beanToJson(Object bean) {           JSONObject json = JSONObject.fromObject(bean);                   return json.toString();       }           /**        * 将java对象转换成json字符串        *      * @param bean        * @return        */    public static String beanToJson(Object bean, String[] _nory_changes, boolean nory) {           JSONObject json = null;                   if(nory){//转换_nory_changes里的属性                         Field[] fields = bean.getClass().getDeclaredFields();             String str = "";             for(Field field : fields){ //              System.out.println(field.getName());                 str+=(":"+field.getName());             }             fields = bean.getClass().getSuperclass().getDeclaredFields();             for(Field field : fields){ //              System.out.println(field.getName());                 str+=(":"+field.getName());             }             str+=":";             for(String s : _nory_changes){                 str = str.replace(":"+s+":", ":");             }             json = JSONObject.fromObject(bean,configJson(str.split(":")));                       }else{//转换除了_nory_changes里的属性                                         json = JSONObject.fromObject(bean,configJson(_nory_changes));         }                                       return json.toString();       }      private static JsonConfig configJson(String[] excludes) {                      JsonConfig jsonConfig = new JsonConfig();                      jsonConfig.setExcludes(excludes);    //                 jsonConfig.setIgnoreDefaultExcludes(false);    // //              jsonConfig.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);    //              jsonConfig.registerJsonValueProcessor(Date.class,    // //                  new DateJsonValueProcessor(datePattern));                                      return jsonConfig;                  }                 /**      * 将java对象List集合转换成json字符串        * @param beans      * @return      */    @SuppressWarnings("unchecked")     public static String beanListToJson(List beans) {                   StringBuffer rest = new StringBuffer();                   rest.append("[");                   int size = beans.size();                   for (int i = 0; i < size; i++) {                           rest.append(beanToJson(beans.get(i))+((i<size-1)?",":""));           }                   rest.append("]");                   return rest.toString();       }           /**      *       * @param beans      * @param _no_changes      * @return      */    @SuppressWarnings("unchecked")     public static String beanListToJson(List beans, String[] _nory_changes, boolean nory) {                   StringBuffer rest = new StringBuffer();                   rest.append("[");                   int size = beans.size();                   for (int i = 0; i < size; i++) {             try{                 rest.append(beanToJson(beans.get(i),_nory_changes,nory));                 if(i<size-1){                     rest.append(",");                 }             }catch(Exception e){                 e.printStackTrace();             }         }                   rest.append("]");                   return rest.toString();       }       /**        * 从json HASH表达式中获取一个map，改map支持嵌套功能        *      * @param jsonString        * @return        */    @SuppressWarnings({ "unchecked" })     public static Map jsonToMap(String jsonString) {                   JSONObject jsonObject = JSONObject.fromObject(jsonString);         Iterator keyIter = jsonObject.keys();         String key;         Object value;         Map valueMap = new HashMap();           while (keyIter.hasNext()) {                           key = (String) keyIter.next();             value = jsonObject.get(key).toString();             valueMap.put(key, value);                       }           return valueMap;     }           /**      * map集合转换成json格式数据      * @param map      * @return      */    public static String mapToJson(Map<String, ?> map, String[] _nory_changes, boolean nory){                   String s_json = "{";                    Set<String> key = map.keySet();          for (Iterator<?> it = key.iterator(); it.hasNext();) {              String s = (String) it.next();              if(map.get(s) == null){                                 }else if(map.get(s) instanceof List<?>){                  s_json+=(s+":"+JsonPluginsUtil.beanListToJson((List<?>)map.get(s), _nory_changes, nory));                                }else{                  JSONObject json = JSONObject.fromObject(map);                  s_json += (s+":"+json.toString());;              }                             if(it.hasNext()){                  s_json+=",";              }         }            s_json+="}";         return s_json;      }       /**        * 从json数组中得到相应java数组        *      * @param jsonString        * @return        */    public static Object[] jsonToObjectArray(String jsonString) {                   JSONArray jsonArray = JSONArray.fromObject(jsonString);                   return jsonArray.toArray();       }           public static String listToJson(List<?> list) {                   JSONArray jsonArray = JSONArray.fromObject(list);                   return jsonArray.toString();       }       /**        * 从json对象集合表达式中得到一个java对象列表        *      * @param jsonString        * @param beanClass        * @return        */    @SuppressWarnings("unchecked")     public static <T> List<T> jsonToBeanList(String jsonString, Class<T> beanClass) {           JSONArray jsonArray = JSONArray.fromObject(jsonString);         JSONObject jsonObject;         T bean;         int size = jsonArray.size();         List<T> list = new ArrayList<T>(size);           for (int i = 0; i < size; i++) {               jsonObject = jsonArray.getJSONObject(i);             bean = (T) JSONObject.toBean(jsonObject, beanClass);             list.add(bean);           }                   return list;       }       /**        * 从json数组中解析出java字符串数组        *      * @param jsonString        * @return        */    public static String[] jsonToStringArray(String jsonString) {           JSONArray jsonArray = JSONArray.fromObject(jsonString);         String[] stringArray = new String[jsonArray.size()];         int size = jsonArray.size();           for (int i = 0; i < size; i++) {               stringArray[i] = jsonArray.getString(i);           }           return stringArray;     }       /**        * 从json数组中解析出javaLong型对象数组        *      * @param jsonString        * @return        */    public static Long[] jsonToLongArray(String jsonString) {           JSONArray jsonArray = JSONArray.fromObject(jsonString);         int size = jsonArray.size();         Long[] longArray = new Long[size];                   for (int i = 0; i < size; i++) {                           longArray[i] = jsonArray.getLong(i);           }                   return longArray;               }       /**        * 从json数组中解析出java Integer型对象数组        *      * @param jsonString        * @return        */    public static Integer[] jsonToIntegerArray(String jsonString) {           JSONArray jsonArray = JSONArray.fromObject(jsonString);         int size = jsonArray.size();         Integer[] integerArray = new Integer[size];                   for (int i = 0; i < size; i++) {                           integerArray[i] = jsonArray.getInt(i);           }                   return integerArray;               }       /**        * 从json数组中解析出java Double型对象数组        *      * @param jsonString        * @return        */    public static Double[] jsonToDoubleArray(String jsonString) {           JSONArray jsonArray = JSONArray.fromObject(jsonString);         int size = jsonArray.size();         Double[] doubleArray = new Double[size];                   for (int i = 0; i < size; i++) {                           doubleArray[i] = jsonArray.getDouble(i);           }                   return doubleArray;               }   } 

package com.mai.json;import static org.junit.Assert.assertEquals;import java.util.ArrayList;import java.util.Date;import java.util.HashMap;import java.util.Iterator;import java.util.List;import java.util.Map;import net.sf.ezmorph.Morpher;import net.sf.ezmorph.MorpherRegistry;import net.sf.ezmorph.bean.BeanMorpher;import net.sf.json.JSONArray;import net.sf.json.JSONObject;import net.sf.json.util.JSONUtils;import org.apache.commons.beanutils.PropertyUtils;import org.junit.Test;public class JsonLibTest {    /*     *  普通类型、List、Collection等都是用JSONArray解析     *       *  Map、自定义类型是用JSONObject解析     *  可以将Map理解成一个对象，里面的key/value对可以理解成对象的属性/属性值     *  即{key1:value1,key2,value2......}     *      * 1.JSONObject是一个name:values集合，通过它的get(key)方法取得的是key后对应的value部分(字符串)     *         通过它的getJSONObject(key)可以取到一个JSONObject，--> 转换成map,     *         通过它的getJSONArray(key) 可以取到一个JSONArray ，     *      *      */        //一般数组转换成JSON    @Test    public void testArrayToJSON(){        boolean[] boolArray = new boolean[]{true,false,true};          JSONArray jsonArray = JSONArray.fromObject( boolArray );          System.out.println( jsonArray );          // prints [true,false,true]      }            //Collection对象转换成JSON    @Test    public void testListToJSON(){        List list = new ArrayList();          list.add( "first" );          list.add( "second" );          JSONArray jsonArray = JSONArray.fromObject( list );          System.out.println( jsonArray );          // prints ["first","second"]      }            //字符串json转换成json， 根据情况是用JSONArray或JSONObject    @Test    public void testJsonStrToJSON(){        JSONArray jsonArray = JSONArray.fromObject( "[‘json‘,‘is‘,‘easy‘]" );          System.out.println( jsonArray );          // prints ["json","is","easy"]      }            //Map转换成json， 是用jsonObject    @Test    public void testMapToJSON(){        Map map = new HashMap();          map.put( "name", "json" );          map.put( "bool", Boolean.TRUE );          map.put( "int", new Integer(1) );          map.put( "arr", new String[]{"a","b"} );          map.put( "func", "function(i){ return this.arr[i]; }" );                    JSONObject jsonObject = JSONObject.fromObject( map );          System.out.println( jsonObject );      }        //复合类型bean转成成json    @Test    public void testBeadToJSON(){        MyBean bean = new MyBean();        bean.setId("001");        bean.setName("银行卡");        bean.setDate(new Date());                List cardNum = new ArrayList();        cardNum.add("农行");        cardNum.add("工行");        cardNum.add("建行");        cardNum.add(new Person("test"));                bean.setCardNum(cardNum);                JSONObject jsonObject = JSONObject.fromObject(bean);        System.out.println(jsonObject);            }        //普通类型的json转换成对象    @Test    public void testJSONToObject() throws Exception{        String json = "{name=\"json\",bool:true,int:1,double:2.2,func:function(a){ return a; },array:[1,2]}";          JSONObject jsonObject = JSONObject.fromObject( json );         System.out.println(jsonObject);        Object bean = JSONObject.toBean( jsonObject );         assertEquals( jsonObject.get( "name" ), PropertyUtils.getProperty( bean, "name" ) );          assertEquals( jsonObject.get( "bool" ), PropertyUtils.getProperty( bean, "bool" ) );          assertEquals( jsonObject.get( "int" ), PropertyUtils.getProperty( bean, "int" ) );          assertEquals( jsonObject.get( "double" ), PropertyUtils.getProperty( bean, "double" ) );          assertEquals( jsonObject.get( "func" ), PropertyUtils.getProperty( bean, "func" ) );          System.out.println(PropertyUtils.getProperty(bean, "name"));        System.out.println(PropertyUtils.getProperty(bean, "bool"));        System.out.println(PropertyUtils.getProperty(bean, "int"));        System.out.println(PropertyUtils.getProperty(bean, "double"));        System.out.println(PropertyUtils.getProperty(bean, "func"));        System.out.println(PropertyUtils.getProperty(bean, "array"));                List arrayList = (List)JSONArray.toCollection(jsonObject.getJSONArray("array"));        for(Object object : arrayList){            System.out.println(object);        }            }            //将json解析成复合类型对象, 包含List    @Test    public void testJSONToBeanHavaList(){        String json = "{list:[{name:‘test1‘},{name:‘test2‘}],map:{test1:{name:‘test1‘},test2:{name:‘test2‘}}}";//        String json = "{list:[{name:‘test1‘},{name:‘test2‘}]}";        Map classMap = new HashMap();        classMap.put("list", Person.class);        MyBeanWithPerson diyBean = (MyBeanWithPerson)JSONObject.toBean(JSONObject.fromObject(json),MyBeanWithPerson.class , classMap);        System.out.println(diyBean);                List list = diyBean.getList();        for(Object o : list){            if(o instanceof Person){                Person p = (Person)o;                System.out.println(p.getName());            }        }    }            //将json解析成复合类型对象, 包含Map    @Test    public void testJSONToBeanHavaMap(){        //把Map看成一个对象        String json = "{list:[{name:‘test1‘},{name:‘test2‘}],map:{testOne:{name:‘test1‘},testTwo:{name:‘test2‘}}}";        Map classMap = new HashMap();        classMap.put("list", Person.class);        classMap.put("map", Map.class);        //使用暗示，直接将json解析为指定自定义对象，其中List完全解析,Map没有完全解析        MyBeanWithPerson diyBean = (MyBeanWithPerson)JSONObject.toBean(JSONObject.fromObject(json),MyBeanWithPerson.class , classMap);        System.out.println(diyBean);                System.out.println("do the list release");        List<Person> list = diyBean.getList();        for(Person o : list){            Person p = (Person)o;            System.out.println(p.getName());        }                System.out.println("do the map release");                //先往注册器中注册变换器，需要用到ezmorph包中的类        MorpherRegistry morpherRegistry = JSONUtils.getMorpherRegistry();        Morpher dynaMorpher = new BeanMorpher( Person.class,  morpherRegistry);          morpherRegistry.registerMorpher( dynaMorpher );                          Map map = diyBean.getMap();        /*这里的map没进行类型暗示，故按默认的，里面存的为net.sf.ezmorph.bean.MorphDynaBean类型的对象*/        System.out.println(map);　　　　　　/*输出:　　　　　　　　{testOne=net.sf.ezmorph.bean.MorphDynaBean@f73c1[　　　　　　　　  {name=test1}　　　　　　　　], testTwo=net.sf.ezmorph.bean.MorphDynaBean@186c6b2[ 　　　　　　　　 {name=test2}　　　　　　　　]}　　　　　　*/        List<Person> output = new ArrayList();          for( Iterator i = map.values().iterator(); i.hasNext(); ){              //使用注册器对指定DynaBean进行对象变换           output.add( (Person)morpherRegistry.morph( Person.class, i.next() ) );          }                  for(Person p : output){            System.out.println(p.getName());　　　　　　　　/*输出:　　　　　　　　　　test1　　　　　　　　　　test2　　　　　　　　*/        }            }            } http://www.cnblogs.com/mailingfeng/archive/2012/01/18/2325707.html